## Example 2.6.3. Lokta-Volterra

import sympy as sy
import sympy.plotting as syp

x, y = sy.symbols('x y')
mu1=1
delta1=0.1
lambda1=1.5
sigma1=0.075
C=2

G=delta1*x + sigma1*y - mu1*sy.log(x) - lambda1*sy.log(y) - C
p=syp.plot_implicit(G, (x,0,100), (y,0,200), line_color='b')

p.save('fig-lokta.png')
